The longstanding challenge in superconductivity research was finding a room temperature superconducting material. The search for room temperature superconductivity was renewed after the discovery of unconventional copper based superconductors with critical temperatures as high as 133 K at ambient pressure. The BCS theory provides clues for achieving high critical temperatures for conventional superconductors. The theory suggests that high frequency Debye phonons, strong electron-phonon interactions, and high density of states can enhance the critical temperatures of conventional superconductors. Following these clues, magnesium diboride (MgB\(_2\) ) has been synthesized and found to be superconducting below 39 K at ambient pressure [1]}, [2]}. The high frequency phonon spectrum due to the light elements in MgB\(_2\)  is believed to be the reason for this relatively higher critical temperature. Based on the idea of high phonon frequency due to the light hydrogen atom, Ashcroft proposed the possibility of having high temperature phonon based superconductivity in hydrogen rich materials, if attractive pairing interaction exists [3]}, [4]}. Ascroft’s proposal was pioneered by the idea of a chemical pre-compression effect proposed by Gilman [5]}. Gilman’s proposal of achieving high temperature superconductors came soon after the discovery of ambient pressure hydrogen rich superconductors Th\(_{4}\) H\(_{15}\)  at a critical temperature of 8 K [6]}. Motivated by Gilman’s idea and the discovery of a hydride superconductor, subsequent studies on Pd–H and Pd–Cu–H systems were reported to exhibit superconductivity below 10 K [7]}. Despite the support of calculations showing that metallic hydrogen is a good candidate for a room temperature superconductor, all experimental efforts turned out be negative for pure hydrogen. Therefore, researchers shifted their efforts toward binary and ternary hydride compounds. The density functional theory, Monte-Carlo, and other numerically based calculations [8]}, [9]}, [10]}, [11]}, [12]}, [13]}, [14]}, [15]}, [16]}, [17]}, [18]} and the discovery of phonon based high temperature superconductivity in H\(_3\) S at high pressure [19]} ignited a wealth of research by synthesizing superhydrides at very high pressure values. To date, about dozen synthesized superhydrides have shown to be near-room temperature superconductors at high pressure. These include phosphorous hydrides [20]}, lanthanum hydrides [21]}, [22]}, [23]}, yttrium hydrides [24]}, [25]}, [26]}, thorium hydrides [27]}, binary cerium hydrides [28]}, ternary lanthanum-yttrium hydrides [29]} and carbonaceous-sulfur hydride ternary compounds [30]}. The most notable among these compounds are the lanthanum hydride [21]}, [22]}, [23]} and carbonaceous sulfur hydride (C-S-H) systems [30]}. Two recent experiments by Drozdov et al [21]} and Snider et al [30]} report near-room temperature superconductivity for LaH\(_{10}\)  at pressure 267 GPa and room temperature superconductivity for C-S-H at pressure 275 GPa. The superconductivity of these compounds was confirmed by the observation of zero resistance and magnetic susceptibility. Furthermore, these experiments show a decrease in critical temperature in the presence of an external magnetic field. The conventional nature of the superconductivity in these compounds was confirmed by a pronounced isotope effect on the critical temperature. The experimental estimates further support that these clathrate-like hydrides superconductors are strongly type-II.
